Pre-loaded valve follower sealing apparatus

Abstract

The improved pre-loaded valve follower sealing apparatus comprises a follower ring and flange insert assembly. The assembly includes a pair of hollow cylinders compressively containing a follower preload and sealing element. That follower preload and sealing element is substantially annular in shape, but has an interior fluid contacting surface which is concave in transverse cross-section when not under compression, but which is rendered substantially smoothly cylindrical when placed under compression.

What is claimed is: 
     
       1. An improved pre-loaded valve follower sealing apparatus for preventing contamination of the interior portions of a valve, such sealing apparatus comprising: a valve body having a valve guillotine supportingly disposed for reciprocating movement therein;   inlet flange and outlet flange means oppositely disposed upon the exterior of said valve body;   a valve seat disposed within said valve body and connected to one of said inlet and outlet flanges to open thereinto; and   a follower ring and flange insert assembly adjacently disposed for forming a follower preload and sealing element containing space therebetween; said (a) follower ring and flange insert assembly comprising:   a pair of hollow cylinders, one of which is snugly and slidingly interdisposed within the other;   a follower preload and sealing element disposed within said follower preload and sealing element containing space formed by said interdisposed cylinders, said follower preload and sealing element being substantially annular in shape, but with the interior fluid contacting surface thereof being concave in transverse cross-section when not under compression to be rendered substantially smoothly cylindrical when disposed under the compressive pressure of said preload conditions within said follower preload and sealing element containing space, and to form a substantially smooth cylindrical surface within said valve to minimize turbulence of the fluid passing through said follower preload and sealing element and impinging upon said interior fluid contacting surface thereof; and   force directing and sealing means for simultaneously sealing the interior of said valve body from fluid leakage through said interdisposed cylinders and for applying force in the direction of said guillotine upon said follower preload and sealing element, and thereby upon said follower ring, to preload said follower ring against said guillotine for maintaining liquid sealing between said guillotine and said follower ring on one side of said guillotine, and between said guillotine and said valve seat on the opposite side of said guillotine.   
     
     
       2. The improved valve sealing apparatus of claim 1 wherein said follower preload and sealing element further includes a generally annular-shaped groove circumferentially disposed in the exterior diameter thereof, and defining outwardly extending legs and for facilitating said substantially smoothly cylindrical shape to the interior surface thereof during compression by means of application of compressive pressure thereto within said follower pre-load and sealing element containing space. 
     
     
       3. The improved valve sealing apparatus of claim 2 wherein transverse cross-sectional shape of said annular-shaped groove is selected from the group consisting of substantially rectangular and rhomboidal. 
     
     
       4. The improved valve sealing apparatus of claim 2 wherein the transverse dimension of said annular shaped groove comprises approximately 35% of the transverse thickness of said follower preload and sealing element at the exterior circumferential surface thereof. 
     
     
       5. The improved valve sealing apparatus of claim 1 wherein said pair of interdisposed cylinders comprising said follower ring and flange insert assembly are substantially L-shaped in transverse cross-section. 
     
     
       6. The improved valve sealing apparatus of claim 1 wherein said valve seat includes an annular-shaped lip portion of larger diameter than said respective valve body opening to which it is sealingly connected to form a circumferential seal around said respective valve body opening. 
     
     
       7. The improved valve sealing apparatus of claim 6 further comprising a gasket disposed between a portion of said respective annular-shaped lip portion and said valve body around said respective valve body opening. 
     
     
       8. The improved valve sealing apparatus of claim 1 wherein said flange insert includes an annular-shaped lip portion of larger diameter than said respective valve body opening to which it is sealingly connected to form a circumferential seal around said respective valve body opening. 
     
     
       9. The improved valve sealing apparatus of claim 1 wherein said follower preload and sealing element is formed from an elastomeric material. 
     
     
       10. The improved valve sealing apparatus of claim 1 wherein said valve guillotine moves in a longitudinal direction within said valve body. 
     
     
       11. The improved valve sealing apparatus of claim 1 wherein said valve seat is sealingly connected to one of said inlet and outlet flanges. 
     
     
       12. The improved valve sealing apparatus of claim 1 wherein said follower preload and sealing element containing space is defined by said shoulder of one said interdisposed cylinder and the top extremity of said other interdisposed cylinder. 
     
     
       13. The improved valve sealing apparatus of claim 1 wherein said follower preload and sealing element concave interior surface has a curvature of approximately 0.41R where in the incompressed state. 
     
     
       14. The improved valve sealing apparatus of claim 1 wherein said follower preload and sealing element has lateral, top and bottom, surfaces which radially extend from the exterior diameter of the follower preload and sealing element to the interior diameter of the follower preload and sealing element at an angle of approximately 2° when in the uninstalled state. 
     
     
       15. The improved valve sealing apparatus of claim 1 wherein the transverse thickness of said follower preload and sealing element comprises approximately 13% of the interior diameter thereof. 
     
     
       16. The improved valve sealing apparatus of claim 1 wherein the transverse thickness of said follower preload and sealing element comprises approximately 11% of the exterior diameter thereof. 
     
     
       17. The improved valve sealing apparations of claim 1 wherein one said cylinder has a shoulder of reduced diameter on the inner diameter thereof. 
     
     
       18. In a valve having a valve body including a fluid flow passage through a guillotine which is disposed between a valve follower and a valve seat, the improvement comprising: sealing and urging means disposed adjacent the valve follower and opposite the guillotine for urging the valve follower into contact with the guillotine and for simultaneously sealing the fluid flow passage within the valve from leakage of fluid into the valve body, said sealing and urging means including a follower preload and sealing statement which has a concave interior surface when in the uncompressed state but having an interior fluid contacting surface which is substantially smoothly cylindrical when in the compressed state; and   means for exterting compressive force to said sealing and urging means at the lateral side thereof which is opposite engagement with the valve follower.   
     
     
       19. The improvement of claim 18 wherein said follower preload and sealing element includes a groove on the outer circumferential surface thereof. 
     
     
       20. The improved valve sealing apparatus of claim 19 wherein said annular groove of said follower preload and sealing element has a groove bottom and defines a pair of legs extending outwardly therefrom at an interior angle of approximately 38° to said groove bottom when in the uncompressed state. 
     
     
       21. The improved valve sealing apparatus of claim 20 wherein said outwardly extending legs are first bent towards each other within said follower preload and sealing element containing space. 
     
     
       22. The improved valve sealing apparatus of claim 21 wherein said follower preload and sealing element is thereafter compressed by application of compressive force within said follower preload and sealing element containing space upon said outwardly extending legs thereof. 
     
     
       23. The improved valve sealing apparatus of claim 22 wherein application of compressive force to said outwardly extending legs renders said interior radiused surface of said follower preload and sealing element substantially smoothly cylindrical in shape. 
     
     
       24. The improved valve sealing apparatus of claim 23 wherein said preload and sealing element interior radiused surface substantially resists bulging inwardly over an extended range of compressive forces within said follower preload and sealing element containing space. 
     
     
       25. The improvement of claim 18 wherein said groove is substantially rectangular in transverse cross-sectional shape. 
     
     
       26. The improvement of claim 18 wherein said groove is substantially rhomboidal in transverse cross-sectional shape. 
     
     
       27. The improved valve sealing apparatus of claim 18 wherein said follower preload and sealing element concave interior surface has a curvature of approximately 0.10R when in the uncompressed state. 
     
     
       28. The improved valve sealing apparatus of claim 18 wherein said follower preload and sealing element concave interior surface has a curvature of approximately 0.10R to approximately 0.41R when in the uncompressed state. 
     
     
       29. The improved valve sealing apparatus of claim 18 wherein said follower preload and sealing element has lateral top and bottom surfaces which radially extend from the exterior diameter of the follower preload and sealing element to the interior diameter thereof at an angle of approximately 15° when in the uninsstalled state. 
     
     
       30. The improved valve sealing apparatus of claim 18 wherein said follower preload and sealing element has lateral top and bottom surfaces which radially extend from the exterior diameter of the follower preload and sealing element to the interior diameter thereof at an angle of approximately 2° to approximately 15° when in the uninstalled state.